Akzo Nobel N.v.

Akzo Nobel Pulp and Performance Chemicals Ab

Joakim Carlén

Fredrik Solhage

Birgitta Johansson

Michael Persson

Freddie Hansson

Annika Viola Pal

Lars Lindahl

The invention relates to a sol containing silica-based particles having an axial ratio of at least about 10 and specific surface area of at least about 600 m2/g. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and S-value up to about 25. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and a specific surface area of at least about 400 m2/g, wherein the silica-based particles are surface-modified. The invention further relates to a sol containing silica-based particles having a viscosity of at least 50 cP and silica content of at least about 3% by weight, wherein the silica-based particles have a specific surface area of at least about 400 m2/g. The invention further relates to a process for producing the aqueous silica-based sol according to the invention, a sol containing silica-based particles obtainable by the process, use of the sol containing silica-based particles as a flocculating agent. The invention further relates to a process for producing paper in which the sol containing silica-based particles is used as a drainage and retention aid.

Silica-based sols

The present invention relates to a process for producing paper which comprises: providing an aqueous suspension comprising cellulosic fibers, adding to the suspension, after all points of high shear, a cationic polysaccharide; an inorganic polymer P1 being a cationic polyaluminium compound; and a polymer P2 being an anionic polymer; and, dewatering the obtained suspension to form paper.

Process for the production of paper

The present invention relates to a process for producing paper which comprises:

The present invention relates to a process for producing paper which comprises: providing an aqueous suspension comprising cellulosic fibers, adding to the suspension, after all points of high shear, a cationic polysaccharide; and a polymer P2 being an anionic polymer; and, dewatering the obtained suspension to form paper.

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Göteborg, Sweden

Joakim Carlén